Field of the Disclosure
Embodiments of the present disclosure generally relate to non-volatile memory, and more specifically to the fabrication of memory elements.
Description of the Related Art
Non-volatile memory is memory that does not require a continuous power supply to retain information. Non-volatile memory may be used for secondary storage or long-term persistent storage. The constantly increasing speed of electronic devices and storage demand drive new requirements for non-volatile memory. Resistive RAM (ReRAM) is one of the leading candidates for high density non-volatile memory.
Resistive memory devices, e.g. resistive switching non-volatile random access memory (ReRAM), are formed using memory elements that have two or more stable states with different resistances. Bi-stable memory has two stable states. A bi-stable memory element can be placed in a high resistance state or a low resistance state by application of suitable voltages or currents. Voltage or current pulses are typically used to switch the memory element from one resistance state to the other. Some kinds of resistive RAM are initially insulating, but a sufficient voltage (known as a forming voltage) applied to the resistive switching material will form one or more conductive pathways in the resistive switching material to prepare a memory device for use.
However, production of ReRAM devices in large quantities is difficult because the behavior of individual cells scatters widely as it is not defined by the material and the geometry, but by random effects. For example impurities or contaminants form as devices are milled into individual units. These contaminants occur in some devices near the edges, where electric fields are the strongest, and/or near the lithographically defined interfaces causing undesired switching. As such, there exists a large variability of electrical properties of individual cells in the fabrication of large arrays.
Thus, there is a need for an improved resistive switching non-volatile random access memory device.